1. Field of the Invention
The present invention relates to a recording device with a copy function.
2. Description of the Related Art
Recently, multifunction facsimile machines that include an electrostatic recording device have become popular. Some multifunction facsimile machines include a printer function and two copy functions. The printer function is for printing out images based on data from an external device, such as a personal computer. The copy functions include a simultaneous retrieval/recording mode copy function and a memory mode copy function.
In the simultaneous retrieval/recording mode, a scanner retrieves image data representing an image of a document. As the image data is being temporarily stored in a memory, a recording unit retrieves the image data from the memory and uses it to print out images of the document. Because the image data is not compressed before being stored in the memory, printing can be rapidly performed. Therefore, the simultaneous retrieval/recording mode is well suited for copying documents quickly.
In the memory mode, image data from the scanner is compressed and stored one page at a time in a memory. Once image data for an entire page of document is stored in memory, the image data is retrieved, decompressed, and used by the recording unit to print out document images. The memory mode is well suited for recording the same image on a plurality of recording sheets using the same compressed data stored in memory.
During the memory mode, a conventional multifunctional facsimile machine follows the timing represented in the timing chart of FIG. 1(a) to consecutively print images at the recording device's maximum speed. That is, before the page that is being presently printed is completely printed out, the memory is checked a timing α to see if image data of the next page to be printed out is stored in the memory. If the memory holds the image data for a subsequent page of images, then the data is retrieved and used for recording the image.
FIG. 1(b) shows the memory check timing used in the memory mode applied in the simultaneous retrieval/recording mode. Because recording units can usually record pages faster than scanners can retrieve images of pages, if the memory is checked at timing a directly before the recording unit records a page worth of image data, then the scanner will not have started retrieving the image data of the next page, so the check will result in a determination that no subsequent document page needs to be printed.
In order to improve durability of facsimile machines, copy machines, and printers, it is desirable to stop transport components, such as a recording sheet transport motor for driving transport rollers for transporting the recording sheets, during times when printing is not being performed. In the situation depicted in FIG. 1(b), the recording sheet transport motor is stopped each time a page of document is printed because no image data for subsequent pages was found to be stored in the memory. Once the image data for a subsequent page is confirmed in the memory, the recording sheet transport motor is started up again.